James Stirrat-Ellis is CEO & Co-Founder of Build, with a mission to make the built world autonomous. He previously designed mega-scale infrastructure at Heatherwick Studio — including Singapore's Changi Airport Terminal 5 — before teaching himself to code and founding his first company. He then joined one of the first agentic startups as CPTO, leading product and engineering through a 10x in revenue and a $24M Series A led by Benchmark. In late 2024 he co-founded Build, a "neofirm" of architects, engineers, domain experts and technologists. Starting with the institutions behind the world's data centers, industrial facilities and energy infrastructure, Build has delivered hundreds of projects across 20 countries, using AI workers to compress months of development work into days.